[OSM-dev] about mercator projection

["Martín RV (OPENGeoMap)"]

Hi:

I am an land surveyor and programmer in Spain.
I would like to talk about the projection used in JOSM and in 
OpenStreetMap. I was studying the projection in Google Earth and World 
Wind, and i think that they have a good choice.

They work always in the geodetic coordinates-*plate carrée*:

x=longitude
y=latitude
http://en.wikipedia.org/wiki/Plate_carr%C3%A9e_projection


Using this method you can always measure distances and angles over the 
ellipsoid using the Vicenty method and don´t need projection conversions:
Here the document:
http://www.ngs.noaa.gov/PUBS_LIB/inverse.pdf
Here source code in javascript and c#:
http://www.movable-type.co.uk/scripts/latlong-vincenty.html
http://www.gavaghan.org/blog/free-source-code/geodesy-library-vincentys-formula/ 


Our ellipsoid is always WGS84




My web is
www.opengeomap.org


Regards.
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